var arith_class = {
	operation: "no_operation",
	operation_sign: "no_sign",
	operation_func: "no_operation_func",
	ans: -1,
	left_rank: -1,
	right_rank: -1,
	ans_rank: -1,
	temp_ans_rank: -1,
	right_ans: -1,
	right_ans_rank: -1,
	right_score = 0,
	wrong_score = 0,
	randomnumber1 = 0,
	randomnumber2 = 0,
	secCounter = 60,
	isGameOver = 0,
	left_nums = [],
	right_nums = [],
	operations = [],
	repetitions = 0,
	isTaskUniq: function(number1, number2) {
		for (i = 0; i < left_nums.length; i++)
			if ((number1 == left_nums[i] && number2 == right_nums[i] &&
				operation == operations[i])||(number2 == left_nums[i] &&
				number1 == right_nums[i] && operation == operations[i]) == 1) {
				return 0;
			}
		return 1;
	}
}